Traditionally the Emperor is seen as representing authority and rulership, the stability and solidness needed to build a civilization.  It symbolizes the traditional power structure in modern, patriarchal society.  This card is the 4th Trump of the Major Arcana.  Four symbolizes earthly reality, basic structure and orientation, and stability - think of the 4 seasons, 4 directions and 4 elements of earth, air, fire and water. 

Two different and yet complementary versions of The Emperor.  On the Olympus card we see Ares standing before a ram while on the Animals Lords card we see a very civilized looking lion with an owl on his wrist.  Once again I was a bit surprised at the Greek god chosen for the Olympus card.  Ares is connected with a lot of things - war, the masculine principle, passion (his affair with Aphrodite was well known).  However I would not have envisioned him being selected to represent stability and solidness or civilization building.  Although now that I think of it I believe the Romans did view Mars as being one of the founders of the Roman state.  Of course considering the Roman propensity for war and conquest, this shouldn't be surprising.  Even the lion is not truly the noblest creature in the forest.  He tends to be a bit lazy and only hunts when absolutely necessary.

Of course what we are talking about here isn't reality but symbolism.  Ares is the symbol of what any "true" ruler should be - masculine, regal assertive and even aggressive.  He is a warrior, willing to take on all comers and defend his land against any potential dangers.  This is the side of The Emperor we all see whenever nation goes to war.  In fact one could argue the the US has had a rather frighteningly half-assed version of this face of The Emperor for the past 8 years.

The Emperor does represent the masculine principle, but there is more to that principle than just aggression and war.  Of course even lions and Ares have more to their personality than just aggression and violence.  Both the cards actually do represent this.  On the Animal Lords Emperor the lion sits on a stump with his sword pointed down towards the ground and an owl (which traditionally symbolizes knowledge and wisdom) perched on his gloved hands.  The gloves may suggest restraint - he only takes the gloves off when it is time to use the sword.  Ares also has his sword pointed down to the ground with both hands on the hilt.  He seems to be leaning on it and watching the actions below him.  Even the ram behind him (often seen as an aggressive and dangerous animal) is still and watchful.  Ares may eventually take action but for how he is being watchful and using his judgment rather than his sword on to resolve the issue.

I have always found it interesting that Ares (the archetypal male) mates with Aphrodite (the archetypal female) to produce Harmonia (their daughter).  The Greeks were sometimes masters of subtlety and the ingenuity.  What genius to show in graphic form that harmony is achieved by the combining of traditionally masculine energy with traditionally feminine energy (or yang and yin).  This is a truly liberating concept too - it reminds us that we don't need to always be peaceful, nurturing and loving - sometimes we can, and need to be, aggressive and assertive.  The trick is to remember that the balance is the key.  Like the lion, we need to conserve this aggressive and sometimes violent nature and only use it when it is necessary and appropriate.  Using that more masculine side wisely and controlling it with mind (not allowing it to control everything) is the best way to ensure that we embody a wise and truly gifted Emperor.